When blanks are to be formed for different types of packaging containers, a material web will, at some point in the conversion process, be provided with fold indications, so-called creases, and possibly also with holes intended for opening devices. A blank which is cut out from the web will then be folded along the creases in order to form a finished packaging container. In particular, this relates to a material web consisting of, or including, a paper or paperboard layer for the manufacture of laminated packaging materials suitable for packing liquid foods. In addition to the creases, the material web is also provided with printed patterns, and so a number of creasing devices, often rollers, are coordinated with a printing press. In order for the finished packaging container to obtain the desired appearance and configuration, with the printed pattern correctly positioned, it is crucial that printed pattern, creases and possible holes are correctly positioned in relation to one another on the material web. In a subsequent forming of packages, it is crucial that printed pattern, creases and holes are in correct mutual relationships or register so as not to disrupt the function of a subsequent filling machine and in order for the printed pattern and the creases to arrive at their intended positions on the final package. Today, this fine adjustment of printed pattern and creases in relation to one another takes place substantially manually when the printing press is made ready for a run. During the run, no control is normally made of whether the printed pattern and creases lie in the correct relationship to one another, which may result in many of the packaging containers departing from the packing and filling machine with more or less incorrect conformity between the printed decorative pattern and the crease pattern, or the holes.
The crease lines extend transversely, or diagonally across, or alternatively longitudinally of the direction of movement of the material web, and the positions of the holes (if any) may be optionally sited between the crease lines.
Holes intended for opening devices may be made in the material web in different ways. Traditionally, the holes are punched mechanically in the same, or a similar operation, as the material web is provided with fold indications. According to more recent technology, holes are cut out in a subsequent operation downstream of the conversion of the material web, this conversion resulting in a laminated packaging material.